CESSATION OF MINING AT LEASED PUEBLO GRAVEL SITE (Details)	3 Months Ended		12 Months Ended
	Oct. 01, 2016 USD ($)	Sep. 27, 2014 T	Dec. 30, 2017 USD ($)	Dec. 31, 2016 USD ($) T
CESSATION OF MINING AT LEASED PUEBLO GRAVEL SITE
Royalties recoverable pending outcome of litigation			$ 627,000
Pueblo Colorado gravel operations
CESSATION OF MINING AT LEASED PUEBLO GRAVEL SITE
Sand and gravel reserves (in tons) | T				50,000,000
Royalties recoverable pending outcome of litigation				$ 1,282,000
Minimum quarterly royalty payment			$ 300,000
Write off of prepaid royalties	$ 632,000
Sand and gravel tons paid for | T		17,700,000
Overpayment of sand and gravel reserve | T		50,000,000